Field of the Invention
The invention relates to a connection device for providing both a connection for transport of a liquid and of electrical power without the use of electrical contacts.
Brief Description of the Related Art
Sensing or measuring the presence or a property of a liquid, e.g. liquid level detection or the measurement of a concentration of an electrolyte, is an exercise widespread in laboratories, clinics, or biotech industry. For example, clinical diagnostic devices often handle liquids, in which case means for the measuring of the presence of the property of the liquid are needed. The presence of a liquid can, for example, be measured by monitoring the signal from a sensor. The signal from the sensor may change according to whether the sensor is in contact with a liquid or not. Other sensors may comprise a moveable sensing element, wherein the signal from the sensor may depend on a position of the sensing element.
Sensing a property of a liquid requires the sensing element of the sensor, e.g. an electrode or a floating element, to come into contact with the liquid. The contact of the sensing element with the liquid generates an electrical signal encoding a sensing value. Evaluation means receive and process the electrical signal and output an outcome of the sensing, e.g. a measurement value or an indication of the presence of the liquid.
Sensors sensing a property of a liquid need to unite in a single device liquid contacts for contacting the liquid and an electrical connection portion for supplying electrical power from a source of electrical power to the sensor. Furthermore, the liquid contacts need to be operatively, e.g. electrically, connected to an electrical sensing circuit for transmission of the sensing value to the evaluation means.
Thus, designing sensors sensing the presence or a property of a liquid is a challenge. The electrical circuit of the sensor for generating the sensing value has to be protected from the liquid in order to avoid corrosion or short circuits.
In the case of liquid level detection, such sensors monitor a filling of a liquid into a container or detect the level of the liquid in the container. The sensing may occur in parallel to the filling of the container. The container is filled using a liquid supply part, for example a pipe or a tubing. Conveniently, a sensor is attached to, disposed at, or integrated into an end portion of the liquid supply part.
The end portion of the liquid supply part may be detachably connected to a supply portion of the liquid supply part. In this case, the detachable end portion of the liquid supply part and the sensor may form a single device. The said single device has to provide for both an electrical connection portion for supplying the sensor with electrical power and a liquid connection portion for supplying liquid to the end portion of the liquid supply part.
In use, the liquid connection portion and the electrical connection portion either establish a liquid and an electrical connection in a substantially simultaneous manner, e.g. by connecting to a hybrid supply, or the liquid connection portion and electrical connection portion are connected consecutively for providing the liquid and the electrical connection.
In the first case of a substantially simultaneous providing of the connections, a damaged liquid supply or a leaking liquid connection can cause liquid to come into contact with the electrical contacts, thus potentially causing a short circuit, which can ruin the electronics in the electrical sensing circuit.
In the second case of a consecutive providing of the connections, when there is an electrical connection, an operator needs to remember to connect the liquid connection portion to the supply portion of the liquid supply part in order to guide the liquid through the end portion of the liquid supply part to the container. Failure of doing so can result in failure of the sensor sensing the presence or a property of the liquid, which can lead flooding devices and possibly result in damaging and/or contamination of the devices. In the case of clinical diagnostic analyses, such contamination can be a risk not only for the operator, but also for the patient. Furthermore, damaged devices may have to be replaced at high costs.